Angiotensin II shows physiological activities such as vasopression by strong contraction of blood vessel, stimulation of aldosterone secretion from adrenal cortex (aldosterone retains sodium), and the like, and is considered to be a causative substance or risk factor of diseases such as hypertension, hypercardia, myocardial infarction, arteriosclerosis, diabetic and non-diabetic renal diseases, vascular restenosis after PTCA (percutaneous transluminal coronary angioplasty) and the like.
It is known that this angiotensin II is generated by cleavage of two amino acid residues from angiotensin I, which is a peptide consisting of ten amino acids present in a living body, and that angiotensin converting enzyme (ACE) is involved in said cleavage. Thus, numerous ACE inhibitors have been developed for the prophylaxis and treatment of the above-mentioned diseases.
Meanwhile, actions of a chymase group including human heart chymase, human mast cell chymase and human cutis chymase, which is one of the subfamilies of serine protease, have been drawing attention in recent years.
It has been clarified that chymase is involved in the course of generation, which is independent from ACE, of angiotensin II in the conversion of the above-mentioned angiotensin I to angiotensin II (Okunishi et al., Jpn. J. Pharmacol. 1993, 62, p. 207 etc. and others). Also, chymase is known to use, as substrates, numerous physiologically active substances such as extracellular matrix, cytokine, substance P, VIP (vasoactive intestinal polypeptide), apoprotein B and the like, and known to be responsible for the activation of other proteases such as collagenase (Igakuno Ayumi, Miyazaki et al., 1995, 172, p. 559).
Therefore, chymase inhibitors are expected to become inhibitors of angiotensin II action, as well as agents for the prophylaxis and treatment of various diseases caused by chymase, since it inhibits generation of ACE non-dependent angiotensin II. A patent application drawn to a chymase inhibitor based on these ideas has been already filed (WO93/25574).
The above-mentioned patent application WO93/25574 in the name of PFIZER INC. discloses a series of peptide compounds which are chymase (inclusive of human heart chymase) inhibitors. However, these compounds are peptide compounds which are unsatisfactory in terms of oral absorption, and no pharmacological test data are available.
Patent applications filed by ZENECA LTD. (Japanese Patent Unexamined Publication Nos. 5-286946, 6-56785 and WO93/21210), J. Med. Chem. 1994, 37, p. 3090, J. Med. Chem. 1994, 37, p. 3303, J. Med. Chem. 1994, 37, p 3313 and others disclose or report heterocyclic compounds which are human leukocyte elastase inhibitors, and these compounds are known to selectively inhibit human leukocyte elastase.
It is therefore an object of the present invention to provide novel compounds having superior chymase inhibitory activity, pharmaceutical compositions thereof and chymase inhibitors.